المؤلفون: Helsen, Lieve, Van Den Bulck, Eric

المصدر: Environmental Science & Technology. 07/15/2000, Vol. 34 Issue 14, p2931. 8p. 1 Diagram, 6 Graphs.

مصطلحات موضوعية: PYROLYSIS, CHROMIUM copper compounds, THERMOGRAVIMETRY, ARSENIC compounds, METALS

مستخلص: Examines the behavior of the metals chromium, copper and arsenic during pyrolysis chromated copper arsenate-treated wood. Relation between the arsenic release and the mass reduction of wood or wood components; Reaction kinetics of the arsenic (As) release; Comparison of the rate of the volatilization of As(III) to the rate of the reduction to As(III).

المؤلفون: Jansen, Jelger^1,2 (AUTHOR) jelger.jansen@kuleuven.be, Jorissen, Filip^1,3 (AUTHOR), Helsen, Lieve^1,2 (AUTHOR)

المصدر: Applied Thermal Engineering. Mar2023, Vol. 223, pN.PAG-N.PAG. 1p.

مصطلحات موضوعية: *RENEWABLE energy sources, *SUPPLY & demand, HEATING from central stations, PREDICTION models, HEATING, NONLINEAR systems

مستخلص: District heating (DH) can help increasing the share of renewable and residual energy sources in the heating sector. Usually a rule-based controller (RBC) is used for controlling these networks while more advanced control strategies like model predictive control (MPC) can support the transition to a decarbonised heating sector. In this paper, an integrated non-linear MPC approach for the control of DH networks is presented. The main novelties are the consideration of the system as a whole (including the heat demand side) and the inclusion of important non-linearities and all types of flexibility in the controller model of the MPC. A simulation-based methodology and dedicated solver are used in which the MPC is applied to an existing fourth generation DH network. The results of a three-day simulation in both a winter and spring period show that the MPC outperforms the currently used RBC: the thermal discomfort is lower in the winter period and comparable in the spring period while the electrical energy use of the DH system is reduced by 3% and 17%, respectively. The MPC achieves these results by lowering the network temperatures, using its anticipatory ability, and exploiting the flexibility of the building thermal inertia. • Development and assessment of a non-linear MPC as system integrator for a district heating system. • The MPC can exploit all types of flexibility in the district heating system. • The MPC is applied to an emulator model of a real-life district heating system. • Simulation results show that MPC outperforms the existing rule-based controller. [ABSTRACT FROM AUTHOR]

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المؤلفون: Hermans, Louis¹ (AUTHOR) louis.hermans@kuleuven.be, Haesen, Robin² (AUTHOR), Uytterhoeven, Anke¹ (AUTHOR), Peere, Wouter^1,2 (AUTHOR), Boydens, Wim^2,3 (AUTHOR), Helsen, Lieve^1,4 (AUTHOR)

المصدر: Applied Thermal Engineering. May2023, Vol. 226, pN.PAG-N.PAG. 1p.

مصطلحات موضوعية: *TOTAL cost of ownership, HEAT storage, SOLAR thermal energy, HEAT pump efficiency, STORAGE tanks, CARBON emissions

مستخلص: Solar districts with seasonal thermal energy storage show great potential in reducing the climate impact of buildings. However, many possible configurations or concepts with different technologies exist for these solar districts. As a result, detailed modelling and simulation of all possible configurations are highly time-consuming and therefore a higher level pre-design phase is often necessary. To limit calculation time, system simplifications are usually applied in this pre-design phase. This paper investigates the effect of two of these simplifications, i.e. fixed coefficient of performance (COP) values for heat pumps and fixed efficiency profiles for solar thermal collectors. In this study, two pre-design methods are developed and investigated, one with the aforementioned system simplifications and one without these simplifications. The methods preliminary size the most important system components and consequently determine the total cost of ownership and CO 2 emissions of each concept. Both approaches are applied to a virtual solar district of 50 residential dwellings for which 4 configurations with a seasonal tank storage and two configurations with a borefield storage are identified. Results show that the method with system simplifications underestimates the total cost of ownership of the configurations with a tank storage by 56%, while it overestimates the total cost of ownership of the configurations with a borefield by 9.3% and the average cost of the borefield concepts changes from being 230 thousand euros higher to being 5.44 million euros lower than the average cost of the tank concepts when the simplifications are refined. Adopting the system simplifications thus results in a completely different selection of preferred configurations, and should therefore be avoided when assessing different concepts for solar districts. • Two pre-design methods for collective solar districts are developed and analysed. • The methods size and assess energy concepts for a virtual residential solar district. • Borefield and tank storage are considered for seasonal thermal energy storage. • The influence of system simplifications is analysed through simulations. • The influence of system simplifications is found to be significant. [ABSTRACT FROM AUTHOR]

: Copyright of Applied Thermal Engineering is the property of Pergamon Press - An Imprint of Elsevier Science and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)